/*
* Copyright 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.keyczar;
import org.apache.log4j.Logger;
import org.keyczar.enums.KeyPurpose;
import org.keyczar.enums.KeyStatus;
import org.keyczar.exceptions.KeyczarException;
import org.keyczar.i18n.Messages;
import org.keyczar.interfaces.EncryptedReader;
import org.keyczar.interfaces.KeyczarReader;
import org.keyczar.util.Util;
import java.util.HashMap;
/**
* Manages a Keyczar key set.
*
* @author steveweis@gmail.com (Steve Weis)
* @author arkajit.dey@gmail.com (Arkajit Dey)
*
*/
public abstract class Keyczar {
private static final Logger LOG = Logger.getLogger(Keyczar.class);
public static final String DEFAULT_ENCODING = "UTF-8";
public static final byte FORMAT_VERSION = 0;
public static final byte[] FORMAT_BYTES = { FORMAT_VERSION };
public static final int KEY_HASH_SIZE = 4;
public static final int HEADER_SIZE = 1 + KEY_HASH_SIZE;
final KeyMetadata kmd;
KeyVersion primaryVersion;
final HashMap<KeyVersion, KeyczarKey> versionMap =
new HashMap<KeyVersion, KeyczarKey>();
final HashMap<KeyHash, KeyczarKey> hashMap =
new HashMap<KeyHash, KeyczarKey>(); // keep track of used hash identifiers
private class KeyHash {
private byte[] data;
private KeyHash(byte[] d) {
if (d.length != KEY_HASH_SIZE) {
throw new IllegalArgumentException();
}
data = d;
}
@Override
public boolean equals(Object o) {
return (o instanceof KeyHash && o.hashCode() == this.hashCode());
}
@Override
public int hashCode() {
return Util.toInt(data);
}
}
/**
* Instantiates a new Keyczar object by passing it a Keyczar reader object
*
* @param reader A KeyczarReader to read keys from
* @throws KeyczarException
*/
public Keyczar(KeyczarReader reader) throws KeyczarException {
// Reads keys from the KeyczarReader
kmd = KeyMetadata.read(reader.getMetadata());
if (!isAcceptablePurpose(kmd.getPurpose())) {
throw new KeyczarException(
Messages.getString("Keyczar.UnacceptablePurpose", kmd.getPurpose()));
}
if (kmd.isEncrypted() && !(reader instanceof EncryptedReader)) {
throw new KeyczarException(
Messages.getString("Keyczar.NeedEncryptedReader"));
}
for (KeyVersion version : kmd.getVersions()) {
if (version.getStatus() == KeyStatus.PRIMARY) {
if (primaryVersion != null) {
throw new KeyczarException(
Messages.getString("Keyczar.SinglePrimary"));
}
primaryVersion = version;
}
String keyString = reader.getKey(version.getVersionNumber());
KeyczarKey key = kmd.getType().getBuilder().read(keyString);
LOG.debug(Messages.getString("Keyczar.ReadVersion", version));
hashMap.put(new KeyHash(key.hash()), key);
versionMap.put(version, key);
}
}
/**
* Instantiates a new Keyczar object with a KeyczarFileReader instantiated
* with the given file location
*
* @param fileLocation
* @throws KeyczarException
*/
public Keyczar(String fileLocation) throws KeyczarException {
this(new KeyczarFileReader(fileLocation));
}
@Override
public String toString() {
return kmd.toString();
}
/**
* Adds a new KeyczarKey (new version) to the key store. Associates it
* with given version. Adds new KeyVersion to the key set.
*
* @param version KeyVersion
* @param key KeyczarKey
*/
void addKey(KeyVersion version, KeyczarKey key) {
hashMap.put(new KeyHash(key.hash()), key);
versionMap.put(version, key);
kmd.addVersion(version);
}
KeyczarKey getPrimaryKey() {
if (primaryVersion == null) {
return null;
}
return versionMap.get(primaryVersion);
}
KeyczarKey getKey(byte[] hash) {
return hashMap.get(new KeyHash(hash));
}
/**
* Returns true if the purpose is acceptable for this key set.
*
* @param purpose
* @return true if the purpose is acceptable, false otherwise.
*/
abstract boolean isAcceptablePurpose(KeyPurpose purpose);
}